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Hot vs. Cold Composting: What’s the Difference?

Any gardener worth his salt knows how using compost can help their garden. 

Often called ‘black gold,’ compost is a nutrient-rich organic substance that is mixed with soil. High-quality compost works as a fertilizer and also helps plants absorb more nutrients in the soil, leading to thriving plants and vibrant gardens. 

While you can buy readymade ‘black gold’ at your local gardening store, many gardeners choose to make compost at home, through the process of composting. 

In this article, we’re going to discuss the differences between hot composting and cold composting. 

What is Composting? 

Composting is the practice of controlling the breakdown of organic matter, such as leaves, wood chips, and food scraps, in a way that forms compost. 

When organic matter is composted, micro bacteria is allowed to break down the matter into a simpler substance that can then be mixed with soil. 

Composting is a great way to dispose of organic waste and be sustainable and also allows you to control the composting process, so you’re more aware of what you’re putting in your garden.

There are several different ways to compost, from vermicomposting to commercial composting. 

When you’re composting in your garden, the two most popular types are cold and hot composting. Understanding the difference between the two and the benefits of both can help you decide which type of composting you want to tackle. 

What is Cold Composting? 

When cold composting, a gardener has to build a pile of organic waste (typically outdoors) and leave it undisturbed for a few months. 

You can keep adding to your cold compost pile, but other than that, no active effort is needed. Cold composting takes six months to a year to break down the waste into compost. 

What is Hot Composting?

Contrary to what its name suggests, ‘hot composting’ doesn’t involve the use of fire or steam to break down organic matter. 

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In this form of composting, the heat comes from the correct combination of nitrogen and carbon, which reacts with air and water to create a ‘hot’ compost pile. 

Essentially, hot composting involves mindfully and strategically mixing the correct ratio of carbon and nitrogen-rich materials. 

When hot composting, you need to mix thirty parts of carbon-rich materials with one part of nitrogen-rich materials. In a matter of days, bacteria will start breaking down the organic matter, and the compost pile will begin to heat up. 

During hot composting, you’ll also have to continuously turn the compost pile, unlike in cold composting, where you leave the compost to its own devices during most of the process. 

When done correctly, hot composting will produce a rich pile of compost within a few weeks. 

Hot Composting Versus Cold Composting: What’s Better? 

Many gardeners agree that hot composting is better than cold composting. Some of the benefits of hot composting over cold composting are: 

  • Hot composting takes much less time than cold composting. When you hot compost right, you’ll have ready compost in a month as opposed to the six months that a cold compost pile will take. Because hot compost piles take less time to break down, it also reduces the amount of space you need to allocate for composting in your garden. 
  • The hot composting process will kill unwanted bacteria. As hot composting brings heat into the composting process, any dangerous bacteria and unwanted pathogens that are sitting in your waste will be killed. Hot composting will also kill weed seeds, which reduces the chance of you having a weed outbreak. 
  • Hot composting reduces the chance of pests. When you leave piles of waste out in your garden, they will likely attract flies, maggots, and other pests. Because of the heat of a hot compost pile, pests will be less likely to set up shop in the waste. 
  • Hot composting can be done all year round. Because hot compost piles get their heat directly from the organic matter, they continue working even in winter. Cold composting stops in winter as cold compost piles rely on heat from the sunlight to warm up. 

However, it’s worthwhile considering that cold composting is a lot less technical and low maintenance. 

If gardening is merely a hobby, you may not have the time and energy to monitor and turn hot compost piles continuously. Additionally, because cold composting doesn’t need specific ratios of materials to work, you can keep adding food waste to it all year round. 

Consider the advantages of both hot and cold composting before you decide which way to go. 

How to Hot Compost 

Gather your waste 

If you decide to hot compost, the first thing to do is to begin setting aside waste for your compost pile. 

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You need to gather thirty parts of carbon-rich waste for every one part of nitrogen-rich waste; in other words, the weight of your carbon-based waste should be thirty times your nitrogen waste. 

Carbon-rich waste (often called browns) includes: 

  • Wood chips
  • Leaves 
  • Shredded newspaper and cardboard
  • Peanut shells
  • Fruit scraps 
  • Corn stalks 

Meanwhile, nitrogen-rich (often called greens) waste includes: 

  • Fish 
  • Grass clippings
  • Food waste (such as vegetable scraps) 
  • Coffee grounds

Each type of substance has different carbon to nitrogen ratios, so it’s worth researching your materials’ carbon and nitrogen count before you begin to compost. 

Build your compost pile 

Create a 4 feet by 4 feet space, which will be home to your compost pile. Start building your pile by alternating layers of browns and green waste, making sure that your green layers are thicker than your brown layers. 

Once you’ve built your pile, wet it thoroughly using a garden hose to start the breakdown process. 

Turn over your pile 

Five days after establishing your compost pile, flip over the entire pile. Continue turning over the pile every two days, using a pitchfork. 

Take the temperature 

Seven days after you build your pile, take its temperature using a compost thermometer. The temperature should ideally be between 131-141 degrees Fahrenheit. 

Two weeks after building your pile, it will start completing its composting process; keep an eye for worms wandering around in your pile. If the worms move in, you know your pile is ready to go!

How to Cold Compost 

Cold composting is a lot simpler than hot composting. To begin cold composting, spend a few days (or weeks) gathering up your composting material. 

The material you can use for cold composting includes: 

  • Kitchen scraps 
  • Leaves 
  • Grass clippings
  • Hair 
  • Seaweed 
  • Shredded newspaper and cardboard. 

While you can also use cow or horse manure in your compost pile, don’t use dog or cat waste as it contains harmful bacteria that won’t be broken down in the composting process. 

Additionally, don’t use meat or dairy waste or weed clippings as a cold composting doesn’t generate enough heat to kill bacteria and weed seeds. 

Once you’ve gathered your materials, build your pile, starting with the food waste in the center, and then adding the leaves and shredded paper. This will stop rats and other pests from getting to the food waste and ruining the composting process. 

Allow your compost pile to sit for three months and then turn it weekly – if you want to. While turning will speed up the process by a few weeks, it’s not necessary for good cold composting. 

Within six months to a year, your compost will be ready – look for worms as a sign that it’s done! 

Once you have rich, brown crumbly compost, it’s time for the next step – adding it to your garden. 

There are several ways to use compost – you can mix it into potting soil or use it as mulch on top of your soil. You can also sprinkle compost over flower and vegetable beds to give them an added boost of nutrients or rake it around trees to help them grow stronger. 

Final Thoughts

Compost is one of the best gardening tools you can have, and making it at home is sustainable and cost-effective. 

Decide whether you want to hot compost or cold compost depending on how much technical research you’re willing to do into composting – and how much time you have. 

ReadyToDIY is the owner of this article. This post was published on December 7, 2019.

As you become more familiar with composting, your skill in it will grow, and you’ll soon be making compost to rival anything you can buy in stores!